Boreholes may be drilled in the earth for many different purposes. As one example, boreholes may be drilled for the purpose of recovering oil and/or gas from subterranean formations. As a second example, boreholes may be drilled for use as water wells. As a third example, boreholes may be drilled for geotechnical, environmental or geo-environmental engineering purposes. As a fourth example, boreholes may be drilled for mineral exploration purposes.
A relatively recent development has been the drilling of boreholes for use in geothermal heat exchange systems. In a geothermal heat exchange system, the ground is used as both a heat source and a heat sink as an alternative to a boiler, furnace, air conditioner etc. in a conventional HVAC system. A geothermal heat exchange system typically involves the use of one or more “earth loops”, which are constructed by drilling a borehole and then installing a heat exchange conduit loop in the borehole.
The drilling of boreholes is generally carried out using drilling rigs of various designs. Relatively robust and sophisticated drilling rigs are often used in oil and gas applications where the boreholes may be relatively deep and/or large in diameter and may be drilled in relatively harsh conditions. Relatively less robust and less sophisticated drilling rigs may often be used for drilling water wells and in geothermal heat exchange applications, since these boreholes tend to be relatively shallow and small in diameter.
In any event, the drilling rig includes a drilling head. A drilling head is a component of the drilling rig which imparts movement to a drill string in order to facilitate drilling. A drilling head is typically either a bottom drive drilling head or a top drive drilling head. The drilling head may also support the drill string, particularly where the drilling head is a top drive drilling head.
The drilling rig often further includes a derrick. A derrick is a structural component of the drilling rig which supports the drill string and associated drilling equipment such as the drilling head while the borehole is being drilled. A derrick may be comprised of any structure which is capable of performing these functions. A derrick may include a mast or may sometimes be referred to as a mast.
A drill string is a length of rod or pipe which extends from the drilling head to the bottom of the borehole during drilling and which typically includes a drill bit at its lower end. A drill string may consist of a continuous length of pipe such as a coiled tubing. More commonly, however, a drill string consists of short sections of rods or conduits described generally as “pipe sections” which are connected together as drilling progresses in order ultimately to provide a drill string of suitable length to drill the desired depth of the borehole. Typically the pipe sections are connected together with threaded box and pin connectors which are located on the opposed ends of the pipe sections.
Among the advantages of using pipe sections to construct a drill string are that the individual pipe sections are relatively easy to transport to and from the drilling site and are relatively easy to handle at the drilling site in comparison with coiled tubing. A disadvantage, however, of using pipe sections to construct a drill string is that procedures must be implemented at the drilling site to transfer the pipe sections to and from the derrick and to connect and disconnect the pipe sections to and from the derrick as drilling progresses.
These procedures are often time consuming and require the participation of several drilling personnel. In addition, these procedures may be inherently dangerous, since they involve the manipulation of the pipe sections, which although relatively short, are also relatively heavy and somewhat unwieldy.
As a result of the disadvantages associated with using pipe sections to construct drill strings, efforts have been made to automate the handling of pipe sections at the drilling site between the location where the pipe sections are stored and the derrick.
U.S. Pat. No. 3,280,920 (Scott) describes an apparatus for drilling wells which includes a mast, a supporting means associated with the mast for rotatably supporting drill pipe, and an elongate frame which is pivoted adjacent the lower end of the mast for swinging movement between a substantially horizontal position and an upright position in which the upper end of the frame is near the supporting means. The frame includes releasable clamps for gripping a section of drill pipe, which clamps are capable of limited reciprocating movement longitudinally of the frame so that sections of drill pipe can be held upright directly beneath the supporting means and can be delivered to the supporting means when the frame is in the upright position. During drilling, individual sections of drill pipe are manually rolled from a storage rack on the drilling floor to the frame, gripped by the clamps, and the frame is then raised by the swinging movement to transfer the sections of drill pipe to the mast. Following drilling, the procedure may be reversed to transfer sections of drill pipe back to the storage rack.
U.S. Pat. No. 3,734,208 (Otto) describes a truck mounted drilling rig which includes a transfer mechanism for transporting sections of drill pipe from a storage position to a drilling position beneath a drive unit mounted on an upright drilling rig mast. The transfer mechanism includes selection means on the drilling rig for removing a section of drill pipe from its storage position and placing it in a pick station, and a transfer arm pivotally attached to the drilling rig and operable to pick the section of drill pipe from the pick station and raise it to a ready station alongside the upright drilling rig mast. The selection means include fore and aft carriages which may be translated vertically to three unload positions on a storage rack which correspond to three tiers in the storage rack. The tiers are defined by cantilivered brackets which include rocker arms at their outer ends. Sections of drill pipe are supported on the three tiers in the storage rack and a section of drill pipe is individually discharged from the storage rack by tilting the rocker arm which is associated with a tier, causing the section of drill pipe to roll off the rocker arm and onto the fore and aft carriages at the appropriate unload position. The fore and aft carriages are then translated vertically to the pick station where the section of drill pipe is picked up by the transfer arm. The transfer arm grasps the section of drill pipe and pivots to raise the drill pipe to the ready station. The transfer arm then swings the section of drill pipe to the drilling position within the mast so that the drill pipe can be connected to the drive unit. The transfer mechanism reverses the above procedure to move sections of drill pipe from the drilling position back to their storage positions.
U.S. Pat. No. 3,734,210 (Wilderman) describes a truck mounted drilling unit which provides for adding and withdrawing sections of pipe to and from a drill string. The drilling unit includes a pipe handling arm which is adapted to grasp individual pipe sections and then pivot to swing the pipe sections between a lower generally horizontal position and a generally upward directed position at or in the mast. The drilling unit also includes two storage racks for the pipe sections, each of which has a bed supporting a plurality of vertically stacked layers of generally horizontally disposed pipe sections. The layers are separated from one another by manually placed spacers which are supported by underlying layers of pipe sections. The bed of each storage rack may be raised or lowered in order to enable one of the layers to be positioned adjacent the lower horizontal position taken by the pipe handling arm. A pipe transfer assembly is provided for individually transferring pipe sections between each of the storage racks and the pipe handling arm. Each pipe transfer assembly includes a pipe flipper associated with the storage rack and a horizontal support zone. The pipe flipper individually engages a pipe section and is actuated to push the pipe section onto the horizontal support zone. The pipe section rolls across the horizontal support zone to the pipe handling arm, where it is grasped by the pipe handling arm. The pipe handling arm then pivots to swing the pipe section through an open side of the mast to the upward directed position where it can be incorporated into the drill string. The above procedure is reversed in order to move pipe sections from the upward directed position back to the storage racks.
U.S. Pat. No. 6,311,788 (Weixler) describes a magazine and manipulation apparatus for drilling rod parts for a drill. The apparatus includes a multi-layered rod magazine in which the layers are separated by manually placed spacer beams which are supported by underlying layers of drilling rod parts, a charging device which transports the individual drilling rod parts to and from the drill, and a removal device for transferring the individual drilling rod parts between the rod magazine and the charging device. In order to facilitate the transport of drilling rod parts to the drill, the magazine pivots to direct the drilling rods toward or away from the removal device. The removal device is then moved vertically downward in order to remove a drilling rod part from the uppermost layer of the rod magazine. The removal device is then moved vertically upward and pivoted 180 degrees by a pivot mechanism in order to transfer the drilling rod part to a bearing unit associated with the charging device, where the drilling rod part is clamped by the charging device. The charging device then transports the drilling rod part to a perpendicular position so that the drilling rod part can be connected with a drilling train which includes a drilling head. In order to facilitate the transport of drilling rod parts back to the magazine, the above procedure is reversed.
U.S. Patent Application Publication No. US 2003/0170095 A1 (Slettedal), dated Sep. 11, 2003 describes a pipe handling device which includes a transport carriage for transporting pipes between a pipe rack and a place of use, wherein the transport carriage includes picking devices that are capable of picking up pipes at different levels in a pivotable layered pipe rack. The layers of the pipe rack are defined by supporting arms which support the pipes and which are swung to the side when a layer is empty to allow access to pipes supported on an underlying supporting arm. Each of the picking devices includes two picking columns. Each of the picking columns has a first picking arm which moves substantially vertically along one side of the picking column. The first picking arms are capable of lifting a horizontal pipe from the pipe rack. Each of the picking columns further includes a second picking arm which moves substantially vertically on the opposite side of the picking column as the first picking arm. In use of the device, a pipe is picked up from the uppermost layer of the pipe rack by the first picking arm and is carried vertically upward. As the pipe approaches the top of the picking column, the second picking arm is moved upward so that the pipe may be held between the first picking arm and the second picking arm. The picking arms then move the pipe vertically above the picking column so that the pipe can be gripped by grappler claws on a pipe erecting device. The pipe erecting device is then moved along horizontal guide rails in order to move the pipe erecting device from a horizontal position to a substantially vertical orientation adjacent a derrick. The grappler claws are then manipulated to move the pipe away from the pipe erecting device and toward the interior of the derrick so that the pipe can be connected into a drill string. In order to return the pipe to the pipe rack from the derrick, the above procedure is reversed.
U.S. Patent Application Publication No. US 2003/0196791 A1 (Dunn et al), dated Oct. 23, 2003 describes a pipe handling system which includes at least one pipe magazine, a pipe conveyor and a pipe arm. The pipe magazine includes vertically spaced horizontal slats for supporting pipe sections thereon and the pipe magazine is pivotable to direct the pipe sections contained therein toward or away from a vertical conveyor. The horizontal slats are individually movable toward the vertical conveyor. The vertical conveyor has a shovel arm for moving a pipe section along the vertical conveyor. The vertical conveyor extends upward to a set of horizontal conveyors. The horizontal conveyors also include shovel arms and extend horizontally to a horizontal position of the pipe arm. The pipe arm is pivotable about its lower end between the horizontal position and a vertical position. In the vertical position, the pipe arm is located at a staging position which is offset from the centerline of the wellbore being drilled. The pipe arm may be actuated to move from the staging position to the centerline of the wellbore. In use, a pipe section may be delivered to a drilling structure by tilting the pipe magazine toward the vertical conveyor, actuating one of the horizontal slats to extend it to the shovel arm on the vertical conveyor, allowing a pipe section to roll from the horizontal slat onto the shovel arm, moving the shovel arm with the vertical conveyor so that the pipe section can be transferred to the horizontal conveyors, moving the pipe section along the horizontal conveyors to the pipe arm, grasping the pipe section with the pipe arm, pivoting the pipe arm to deliver the pipe section to the staging position, and actuating the pipe arm to deliver the pipe section to the centerline of the wellbore. In order to deliver pipe sections back to the pipe magazine, the above procedure is reversed.
There remains a need for an apparatus and a method for handling pipe sections which is relatively simple and robust. There is also a need for an apparatus for handling pipe sections which is capable of accommodating pipe sections having different diameters either with no modification of the apparatus or with only minor modification of the apparatus.